Configuration Structure and Evolutionary Characteristics of Policy Instruments for Marine Protected Areas: A Chinese Policy Text Analysis Based on LDA Topic Modeling and Policy Instrument Theory

The sample for this study was sourced from the National Laws and Regulations Database, using “marine protected areas” as the title search term with a fuzzy matching strategy. The search covered the period from January 1, 1982 to December 31, 2025, yielding 212 policy texts. To ensure a high degree of relevance between the texts and the research topic, manual screening was conducted based on whether the content explicitly addressed marine or coastal ecosystem conservation, covering types such as marine nature reserves, marine special protected areas, marine ranches, coastal wetlands, and island protection. This procedure ultimately yielded 86 MPA policy texts, comprising 8 national laws, 5 administrative regulations, and 73 local regulations, with a temporal distribution spanning from 1982 to 2025. It constitutes a policy text corpus of more than 420,000 Chinese characters, providing a valid data foundation for the subsequent operation and analysis of the LDA topic model.